The present invention relates to a geared air actuator and, more particularly, to a geared air actuator which is adapted to actuate a valve, such as a ball valve.
In the prior art, such actuators have utilized a rack and a pinion drive to operate the valve. Some such actuators have been provided with springs located at the ends of the actuators to enable them to move the actuators back at the end of their thrust. In other such actuators, the springs have been mounted around the outside of a piston. It has been found that existing actuators are bulky and require a separate rack to operate the pinion which, in turn, operates the valve.
Illustrations of actuators which have been used in the prior art are disclosed in U.S. Pat. No. 4,716,815 which shows a spring-passed two-way piston and U.S. Pat. No. 2,848,186 which discloses an actuator having a spring in a bore in one end of a solid elongated piston body.